Merkel's governing coalition and opposition lawmakers established a parliamentary committee in March to investigate the scope of the NSA spying. The committee decided Thursday to try to question Snowden directly, German news agency dpa reported.

It's not yet clear if they will invite Snowden to Germany or interview him via video conference.

Opposition parties insist Snowden should be brought to Berlin as a key witness, while Merkel's governing coalition has opposed that. The U.S. has revoked Snowden's passport, meaning he would need the government's help to enter Germany.